Relay control circuit



Sept. 22, 1931.

c. R. B ooks 1,824,194

RELAY CONTROL CIRCUIT Filed Sept. 26, 1929 Inusn DP Charles RBmuks Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE CHARLES R. BROOKS, OF CHICAGO, ILLINOIS, ASSIGI I'OR TO RESERVE HOLDING COM- IAJSI'Y, OF CHICAGO, ILLINOIS, A CORPORATION OI DELAWARE RELAY CONTROL Application filed September 26, 1989. Serial No. 895,249.

The present invention relates in general to relay control circuits, but more particular- 1y with the control of,the functioning of a relay when connected up in a circuit which 5 includes a dry. disc rectifier or electronic valve. such as are now in general use. In order to illustrate the'invention the same is incorporated in a well-known type of selector switch used in extending connections from a calling line of an automatic telephone system in the direction of, a called line.

To those familiar with automatic .telephone practice, it is well known that the controlling armature of the line relay of an automatic switch, having the conventional circuits, closes the circuit of the associated release relay when the line relay is energized and closes a circuit for the operating magnet and the associated changeover rela when the line rela deenergizesa In suc circuits, the operating circuit is not closed until the armature spring of the line relay comes into engagement with its resting con- 2 tact, and the circuit of the release relay is not" closed until the said armature spring of the line relay comes o agement with its working centric Con'se ently, the time which elapses while the armature s ring is in its mid-position is suflicient to a low the release relay andthe changeover relay to drop back unless some means are provided to render them slow to release. In the past this result has been accomplished in various ways, i. e., by placing a slug on the core' of the relay, or by placing a igh resistance in multiple with the relay.

While these methods have proved satisfactory to a certain degree, they tend to make the relay somewhat sluggish. onboth the ull up and release operations. It is apphcants object to provide an improved 'arrangement'for accomplishing the desired resnlt by suitably revisin the circuits so that the shunt path aroun the rela is very high to current supplied to the re ay from an exterior source, while this high'resistance path becomes a low resistance path to induce current as soon as the line relay. opens its energizing circuit, so that the maximum amount of induced current generated is free to flow through the relay tp hold it operated while the armature of the line relaytalternately interrupts its energizing circu1 V In an exchange using a number of s%h selectors, it is customary to rovide super visory alarm equipment whic functions to inform an attendant if any switch or switches fail to properly release. To accomplish this it is customary to place a lowresistance slow-to-energize relay in series with the operatin circuits of the release magnets of each 0 a group of such selector switches- This slow-to-energize relay closes an alarm circuit if any release circuit is closed a longer time than is ordinarily required to release a switch.

In accordance with the present invention an ordinary relay is provided in a circuit including a rectifying unit, which functions in a manner to make the relay slow to pull up.

The sin le sheet of drawing shows 'b means of t e usual circuit diagram, a su cient amount of apparatus used in an auto- -matic telephone system to enable the in- .vention to be readily understood.

.The substation A is of the usual automatic type, having the usual talking and signalling instrumentalities and a switch controlling calling device C The lineswitch LS may be of the wellknown rotary type in which the wipers have no normal posit1onand move in a forward direction only.

The selector D is of the well-known vertical pnd rotary type, having 100 sets of bank contacts arranged in ten horizontal rows or levels.

The control circuits of the selector D have been revised so as to embody the principles of the invention.

In order to explain the operation of the improved circuits, it will be assumed that a subscriber at substation A desires to converse with some other subscriber of the system. When the receiver is removed at substation A the lineswitch LS functions in a well-knownmanner to extend the connection to the selector D. The circuit to the selector extends from the negative terminal of battery supplied to the upper windinig of the line relay 35, the'armature 52 an its resting contact, conductor 24, wiper 21, throughthe substation apparatus at A wiper 23, conductor 26, resting contact and armature 55, to the lower winding of the line relay 35 and ground.

The line relay 35, upon energizing, closes a circuit at armature 46 for the release relay 36. This circuit extends from the grounded resting contact and armature 54, armature 46 and its working contact, through the winding of relay 36, to battery and ground. The electronic valve 15, connected in multiple with relay 36 is so poled with respect to the battery that it prevents the flow of any appreciable current directly supplied by the battery from passing around the relay36. The relay 36, upon energizing, at armature 48 opens a pointin the circuit of the-release magnet 41 and prepares a circuit'for the vertical magnet 40, andat armature 47* places ground on the release trunk conductor 25, thereby closing the usual olding circuit for the lineswitch LS. I

Y The calling subscriber now operates the calling device CD in accordance with the first digit of the desired number, whereupon the circuit of line relay 35 is opened. a corresponding number of times at the calling substation. Each time line relay 35 deenergizes in response to one of the interruptions produced in its circuit, it opens the initial circuit of release relay 36- and closes the following series circuit-for the changeoverrelay 37' and vertical magnet .40, from ground at. the resting contact and armature 54, armature 46 and its resting contact,

armature 48 and its worln'ng contact,

through the changeover relay 37, and winding of vertical magnet 40, to battery. The electronic valve, in multiple with 37, is so poled with respect to the battery that, it prevents any appreciable current flow from the battery around the relay 37. The resistance of relay 37 is comparativelydow and consequently the vertical magnet is energized upon each deenergization of the line relay 35 toelevate the wipers of the switch D to the desired level of .bank contacts in the usual manner. Each time the line relay 35 restores its armature it opens the traced circuit for relay 36, but the relay 36 does not deenergize because the decrease in electromagnetic saturation of the relay core which occurs when its energizing circuit isopened causes an E. to be induced in its own winding in the same direction as that formerly supplied by the battery. This induced E; follows the low resistance path provided, by the valve 15 which tends to deay the release action of the relay by prothe " current sent to the vertical magnet 40, as pointed out above, a circuit is closed for the stepping relay 38 at its armature and working contact. This circuit extends from grounded contact and armature 47, through the front contact and armature of relay 37, ofi-normal contacts 44, the interrupter springs of rotary magnet 42, and through the winding of 38 to battery. The stepping relay 38, upon energizing, closes a locking circuit for itself at its armature 50, and at its armature 51 prepares a circuit for the rotary magnet 42.

At the end of the vertical movement, armature 46 comes to rest in an energized position, and series relay 37 being open-circuited for a prolonged interval eventually deenergizes, and at its armature opens the initial circuit of the stepping relay38 and completes the circuit for the rotary magnet 42. The rotary magnet 42, upon energizing, advances the wipers 56-58, inclusive, into engagement with their first set of contacts in the level opposite which they were raised and at the end of its stroke opens the circuit of the stepping relay ,38, at its intcr- I ruptercontacts. Relay 38, upon deenergizing, opens the circuit of the rotary magnet 42 at armature 51, whereupon the rotary magnet 42 deenergizes and again closesits interrupter contacts. Thealternate operation of stepping relay 38 and rotary magnet 42 continues in the usual manner-until an idle or ungrounded trunk 'is reached, whereupon the switching relay. 39 which was heretofore short circuited now energizes in series with the stepping relay 38 over the following circuit: from ground by way of the working contact and armature 47, switching relay 39, oil-normal contacts 44, tl'g interrupter contacts, and the stepping magnet 38 to battery. The stepping relay 38, howover, does not energize at this time on account of the high resistance of the switching relay. The switching relay, however, operates and at its armatu'res 52 and 55 breaks away from its resting contacts and extends the connection to the line relay of the switch ahead, thereby disconnecting the line relay 35. When the line relay 35 is disconnected, armature 46 falls back and again opens the circuit of relay 36, but owingto the slowrelease characteristics of this relay. it does 65 longing the magnetic field of therelay coil; not deenergize until suflicient time has I connection to the called line.

elapsed to permit ground potential, supplied over to conductor 65 from the switch ahead, to. replace that tormerly supplied to the working contact and armature 47.

- The switch seized by the selector D may be a second selector similar to the switch D or .a connector switch for com leting the ince, however, the present invention is not concerned with the type of switches used, it will be sufficient to assume that the subscriber at substation A decides to abandon the call and, therefore, replaces his receiver.

When the receiver is replaced at the substation A the switch seized by the selector D removes ground potential from conductor 65, thereby bringing about he release of the lineswitch LS and the selector D. These switches are both released in the usual and well-known manner,

Attention, however, is called to the release circuit of switch D,'which includes a release alarm relay 56, having its action modified by the presence of an electronic valve 17. When ground potential is removed from conductor 65 the switching relay 39 deenergizes and at its armature 54 andits grounded contact completes the circuit for the release magnet. This circuit extends by way of armature 46 and its resting contact, armature 48 and its resting contact, theoff-normal springs 43, the winding of the release magnet 41, and the winding of the release alarm relay 56 and the electronic valve 17 in multiple, to batte If the switch releases as it should, the 0 -normal springs 43 will open the circuit of release magnet 41 and of the alarm relay 56 before sufficient time has elapsed to cause the alarm relay to operate. This dela in operation of the alarm relay is cause by the action of the valve absorbing a charge which impedes the path of the impressed E. M. F. in direct ratio to the ohmic resistance of the valve in its low resistance direction. This condition persists until the valve receives its maximum charge, at which time the surplus E. M. F. Ipasses to the rela winding to operate it. he relay is quic to restore, however, because the valve acts as a high resistance shunt to current induced in the winding of the release alarm relay 56 when the latter relay circuit is broken.

What is claimed is: v 1. In an operating circuit for a single coil relay having an armature, a source of of conductors extendin from said relay, a battery, one of said in uctors extending to one terminal of said battery, a pair of contacts for intermittently supplying current by way of the other conductor from said battery to the other terminal of said relay to operate the same, and an electronic valve in bridge of said conductors preventing the deenergization of said relay while said contacts are momentarily opened irrespective of the number of times said contacts are opened" so long as'any period of opening does not exceed the maximum first period which they for modifying the influence of the intermittently closed circuit on said relay comprising an electronic valve connected across the terminals of said coil.

4. In a relay control arrangement, a relay, an operating circuit for said relay comprising a source of current and a device for producing series of interruptions in said circuit, and auxiliary means permanently connected across the terminals of said relay having a high resistance to the, current flow it its operating circuit and a low resistance to current induced in said relay flowing. when the operating circuit is interrupted for holding said relay operated during such period.

5. In combination with a single coil relay, an operating circuit therefor including a supply of direct current operatin energy, an electronic valve having an infinite resistance to current flow in one direction and an extremely low resistance to current flow in the reverse direction, means for connecting said valve across the terminals of said. relay to make the same slow to pull up while its former characteristic as regards to its falling away is retained or slow to fall away with like retention of its characteristic as regards its pulling up action depending on the polarity of said valve with respect to said source of energy.

In witness whereof, I hereunto subscribe my name this 23rd day of September, A. D.

CHARLES R. BROOKS.

direct current energy and a circuit closing 6 tion when said circuit is intermittently closed for a prolonged period, depending on the polarity of said valve with respect to said. current.

2. In an impulsing circuit, a relay, a pair 

